Apparatus for refrigerating and liquefyng air or other gases.



No. 642,505. Patented .Ian. 30, I900. E. C. THBUPP.

APPARATUS FOR REFRIGERATING AND LIQUEFYING AIR 0R OTHERGASES.

(Application filed Feb. 28. 1899.;

(No ModeLl 3 Sheets-Sheet 1.

/ Patented Ian. 30, I900. E. C. THRUPP.

APPARATUS FOR BEFBIGERATING AND LIQUEFYING AIR OR OTHER GASES.

(Application filed Feb. 28. 1899.

3 Shaats-Sheet 2.

(No Model.)

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No. 642,505. Patented .Ian. 30, I900.

E. c. THBUPP.

APPABATUS FOB REFRIGERATING AND LIQUEFYING AIR OR OTHER GASES.

(Application filed Feb. 28. 1889.) (No Model.) 3 Shaets-Sheat 3.

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NITED STATES PATENT OFFIC EDGAR C. THRUPP, OF WALTON-UPON-THAMES,ENGLAND.

APPARATUS FOR REFRIGERATING AND LIQUEFYING AIR OR OTHER GASES.

SPECIFICATION forming part of Letters Patent N 0. 642,505, dated January30, 1900.

Application filed February 28, 1899. Serial No. 707,202. (No model.)

To all whom it may concern:

Be it known that I, EDGAR CHARLES THRUPP, civil engineer, a subject ofthe Queen of Great Britain and Ireland, and a resident of Southdene,Ashley Park road, Walton-upon-Thames, in the county of Sur rey, England,have invented certain new and useful Improvements in Apparatus forBefrigerating and Li quefyin gAir or other Gases,

(for which I have applied for a patent in Great Britain, No. 26,767,dated December 19, 1898,) which invention is fully set forth in thefollowing specification.

In refrigerating apparatus depending on compressing air, then coolingit, and then expanding it in a cylinder against a piston doingmechanical work the cooling of the air to extremely low temperaturescannot be effected on account principally of the genera tion of heat bythe friction of the piston against the cylinder-walls of the piston-rodin the glands and in some cases of the valves and their operating-gearand the conduction of heat through the cylinder-walls from outsidesources during the expansion of the air and also on account of thefluctuation of temperature within the expansion-cylinder,which causesheat to be absorbed by the cylinderwalls and piston at the beginning ofthe expansion-stroke and transmitted to the air toward the end of thestroke. It is therefore important to reduce as far as possible thefriction between solid surfaces with which the air may come in contactor proximity during expansion and to keep the expansion cylinder orchamber small, soas to have as little surface as possible exposed to theatmosphere and snrroundin g'objects, and, further, to employ a motorwherein the expansion takes place with very little, if any, fluctuationof the temperature of the air in contact with any particular part of thesurface. It is impossible to obtain all these advantages simultaneouslyin a piston and cylinder motor While expanding the air in a high ratioof volumes.

Another class of apparatus which has been used for obtaining very lowtemperatures, and thereby liquefying gases, depends on the coolingeffect of a jet of air or gas issuing under high pressure from a pipe orreceiver through a very small orifice or cook, the air being cooledwhile under high pressure by part of the cold air discharged, assistedsometimes by other means. The arrangementontirely disposes of theelement of friction of solid surfaces in the expansion-chamber and alsorealizes the desirable conditions of a small chamber with little or nofluctuation of the temperature of its parts during the process ofexpanding the air; but the very large amount, of Work done in overcomingthe resistance of the orifice (apart from the displacement of theatmosphere) is entirely converted into heat, which remains in theexpanded air. Ahigh cooling efficiencyis therefore impossible, althoughextremely low temperatures may be obtained with such apparatus if arelatively large amount of energy be expended in compressing the air.

According to my invention the expansion of the air is carried out in amotorof the turbine type running at a high speed and doing externalwork. Any suitable and efficient form of turbine may be used; but Iconstruct the shaft or spindle bearings and thrust-block (if any) atsome little distance from the Working barrel or chamber for the doublepurpose of avoiding friction of solid surfaces or lubricants near thecold air and preventing the oil-supply being frozen.

If the apparatus be used for liquefying air or other gases, the highratio of expansion required may be secured either by a very high initialpressure in the turbine, with the discharge a little above theatmospheric pressure, or by a moderately high initial pressure and avacuum in the exhaust-box maintained by air-pumps. In the latter casethe liquefied portion of the discharge from the turbine is preferablypumped out of the exhaust-box by a separate pump.

I will now describe, with reference to the accompanying drawings, anarrangement of apparatus according to my invention, premising that I donot limit myself to the particular details of the arrangementillustrated, as any convenient and efficient means the equivalents ofthose set forth may be employed.

Figure 1 is a general diagrammatic plan of the apparatus. Fig. 2 is avertical section of parts of the apparatus on the lines 1 2 3, Fig. 1;and Fig. 3 is an enlarged vertical section of part of the turbine-motor.

S S S represent the cylinders of a tripleexpansion steam-engine, and Lis its crankshaft, carrying the fly-wheel K and driving a three-stagecompressor, the cylinders of which are marked A A A having intermediatewater-coolers XV W The compressed air on leaving the third compressing-cylinder A passes to the cooler 13, which has a circulation ofwater to reduce the temperature of the compressed air to that of theatmosphere or thereabout, and then it passes through the auxiliarycooler O to the main cooler or interchanger D, or it may pass directlyto the said interchanger from the cooler B by the pipe, (indicated bythe dotted lines M.)

The auxiliary cooler C consists of a coil or coils of piping in a tank 0the compressed air passing through the piping and cold brine (which maybe cooled, for example, by an ammonia refrigerating machine) circulatingthrough the tank, entering at N and leaving at N Further cooling of thecompressed air is effected in the interchanger or main cooler D, inwhich the cooling medium is air discharged from the turbine E. Thecompressed air passes through a series of concentric spiral coils d,contained in annular spaces d arranged so that while the compressed airpasses alternately upward and downward in successive coils, travelingtoward the center of the apparatus, the cold exhaust-air enters at thebottom of the central compartment and travels in the reverse direction.This will be understood by reference to Fig. 2, wherein the direction oftravel of the cold exhaust-air alternately upward and downward isindicated by the arrows.

The compressed-air pipe emerges from the bottom of the centralcompartment of the interchanger D and passes to the turbine E and isfitted with a stop-valve P and may also be fitted with a throttle-valveactuated by governor-gear to control the speed of rotation of theturbine, if desired. If moisture be contained in the compressed air, itmay be condensed or converted into snow in passing through the coolers B(J D and may be collected or intercepted by introducing traps at,

any suitable point on the compressed-air-pipe circuit-for instance, asindicated at O O in Fig. 1consisting of boxes or cylinders of largerdiameter than the compressed-air pipe. The traps are shown in duplicate,with stopvalves 011 the inlets and outlets, so that one at a time can beshut off from the compressedair circuit and opened for removing thedeposited moisture or snow. The turbine E (shown in the drawings) is anadaptation of the well-known radial-flow compound steamturbine. Thecompressed air enters the working barrel of the turbine E at the centerby the pipe (1 and travels right and left, as indicated by the arrows inFig. 3, impinging on the projecting vanes carried by the disks X,mounted on the shaft X and directed by fixed guide-blades carried onannular disks projecting inward and forming the barrel. The

covers y direct the air or gas first inward, as it exhaustsfrom theturbine, allowing the liquid to escape at the circumference through apassage communicating with the pipe U, leading to the reservoir G.

Q Q is the center line of the machine in Fig. 3, the halt not shownbeing substantially a repetition of the half shown.

F is the exhaust-box, surrounding the turbine, and R is an annular spacesurrounding the shaft X where it passes through the non-conductin gjacket F of the exhaust-box. The object of the spaces R is to keep thethrust or guide blocks S and the bearings T at a distance from the motorparts of the turhide and from the exhaust-box for the purpose aforesaid.

The liquefied portion of the exhaust may pass away by the pipe orpassage U into the reservoir G, which is provided with a drawoff pipe gat the bottom, a closed top, and an overflow or outlet pipe V for gasexpelled as the liquid runs in or afterward produced by the evaporationof the liquid. The gas which passes out of the reservoir through thepipe V may be passed up the annular space outside the reservoir andallowed to escape through the interchanger D, together with the exhaustfrom the turbine. On leaving the interchanger D the exhaust passes intothe chamber H, containing a central tube h, open to the atmosphere atthe top and to the chamber H at the bottom. Fresh air is drawn inthrough the central tube h to make up for the portion which has beenliquefied, and in passing down the tube it is cooled by the air in thesurrounding chamber H and its moisture condensed. The condensed moistureis drawn off by a trapped drain 71 and the fresh air then mixes with theexhaust-air and passes by the passage 71, to the first compression-cylinder A. If the moisture be separated as snow, it ispreferable to employ duplicate separators similar to H, provided withvalves to shut oft one of the said separators at a time for removing thesnow.

The turbine-shaft 0& is extended beyond one bearing and maydrive acounter-shaft by friction-gearing, as shown at I in Fig. 1, and assistin driving the compressors by a belt passing from the pulley J on thesaid counter-shaft to the fly-wheel K, or it may drive any othermachine, such as a dynamoelectric machine.

The cold portions of the apparatus are all inclosed by non-conductingcoverings, which are indicated by the thick sectioned portions.

The form of turbine-motor shown in the drawings is, I believe, that bestsuited to the purposes of my invention for obtaining the lowesttemperatures but I may use any other suitable form ofturbine-motor-such, for instance, as one resembling the De Lavalsteamturbine or the Pelton Water-wheel or reaction turbines.

The apparatus may be used for separating mixed gases which liquefy atdifferent temperatures, and if so used it may be preferable to preventany of the gas produced by evaporation in the reservoir from mixing withthe exhaustgas from the turbine. It may also be preferable not to returnany of the latter to the compressor, but to take in an entirely freshsupply of mixed gases at each stroke of the compressor.

If the liquefying temperatures of the gases are not very widelydifferent, it may happen that both will be liquefied simultaneously, andthe separation may be effected more or less perfectly by allowing theliquid mixture to stand in a reservoir while the gas, having the lowerboiling-point, evaporates. A convenient way of carrying out thisprinciple is by dividing the reservoir G, Figs. 1 and 2, into two ormore compartments,with pipe connections to enable them to be filled oneat a time and allowed to rest while the other compartments are beingfilled in turn. The gas or gases evaporated from the reservoirs may beused to cool the compressed mixed gases in an interchanger of similarconstruction to D or working on the same principle. This plan issuitable for separating liquid oxygen from liquid nitrogen byevaporating off the nitrogen. If the oxygen is required in the gaseousstate, it may also be used for cooling the compressed air in an anotherinterchanger.

If the liquefying temperatures of the mixed gases are widely different,the degree of compression maybe arranged so that only one of the gasesis liquefied, and the liquid may then be delivered into a reservoirhaving no direct connection with the exhaust-gas passages in theinterchanger; but the liquid may be evaporated and passed through asecond coil of pipes in the interchanger and discharged into agas-holder or other receptacle, as required. The apparatus may be usedin this manner forseparatin g ethylene (and othermore easily condensablehydrocarbons) from ordinary coal-gas or forseparating hydrogen fromcoalgas or water-gas by liquefying the other constituents of themixture.

Having now particularly described and ascertained the nature of my saidinvention and in what manner the same is to be performed, I declare thatwhat I claim is 1. In apparatus for refrigerating and liquefying air,the combination of a turbine inclosed in a non-conducting jacket orcasing having annular spaces around the shaft where it passes throughthe said casing and all thrust or guide blocks and bearingssituatedoutside the said jacket or casing to keep them at a distance from themotor parts of the said turbine, in which the air or gas or gases is orare expanded and caused to do external mechanical work, means forcompressing the air or gas or gases consisting of two or morecompressing-cylinders operating step by step with intermediatecooling-coils and means for cooling the air or gas or gases While underhigh pressure down to a temperature below. the freezing-point of water,a chamber, or chambers in duplicate, through which the air or gas orgases are passed and in which the moisture and other impurities aredeposited mostly as snow, and separated, and a heatinterchanger forfurther cooling the air or gas or gases.

2. In apparatus for refrigerating and liquefying air or other gas orgases the combination of a turbine-motor in which the air or gas orgases, is, or are, expanded and caused to do external mechanical work,means for compressing the air or gas or gases, consisting of two or morecompressing-cylinders, operating step by step with intermediatecooling-coils, and means for cooling the air or gas or gases while underhigh pressure down to a temperature below the freezing-point of Water, achamber or chambers through which the air or gas or gases are passed andin which the moisture and other impurities are deposited and separated,a heat-interchanger for further cooling the air or gas or gases andmeans for passing the said air or gas or gases into the turbine and adevice through which the gaseous portion of the exhaust from the turbineis passed for separating moisture from the fresh-air supply to thecompressor, substantially as hereinbefore described.

3. In combination with apparatus for liquefying air and other gases, areservoir or receptacle'for the liquid, consisting of a cham ber with aclosed top surrounded by an annular space and a thickv inclosure orjacket of insulating material, the said chamber being provided with aninlet-pipe and an outlet-pipe for the liquid and an outlet-pipe for gascommunicating with the lower part of the annular space, substantially ashereinbefore described.

In testimony whereof I have signed this specification in the presence oftwo subscribing witnesses.

I EDGAR O. TI-IRUPP. Witnesses: 1

WILLIAM FREDERICK UProN, R. I. FREEMAN.

